腐蚀与防护-课件

MaterialsCorrosionandProtection

1Instructor:Dr.JingMADepart.ofMetallicMaterialsEngineeringOffice:A344MaterialBuildingE-mail:majingt@BilingualTeachingDemandofeconomicglobalization.ChinaMinistryofEducation“BilingualTeachingCourseReformPlan”,2001Toimprovestudents’learningandacquiringofmakethemcompetentforinternationalcommunicationintheirspecialtyfields.Contentsofthesubject:Chapter1IntroductionChapter2ElectrochemistryFundamentals

Chapter3

GeneralandLocalCorrosionChapter4

NatureCorrosionChapter5OxidationChapter6CorrosionControl

(1)杨德钧，沈卓身,金属腐蚀学.冶金工业版(2)

/mestijaya/cmm/CorrosionandcorrosioncontrolByR.WinstonRevie

很有用的网址：

http://bbsGoogle搜索：MITopencourse何业东，齐慧滨.材料腐蚀与防护概论.机械工业版

腐蚀源于拉丁文“corrdere”，意即“损坏”、“腐烂”Corrosioncanbedefinedasthedegradation

ofamaterial

duetoareaction

withitsenvironment.

材料与环境组分发生的物理的、化学和电化学作用而引起的变质和破坏，称之为腐蚀。

Materials

canbemetals,polymers(plastics,rubbers,etc.),ceramics(concrete,brick,etc.)orcompositesmechanicalmixturesoftwoormorematerialswithdifferentproperties.Chapter1

Questions:?Whatiscorrosion？

Questions:?WhyMetalscorrode？Metalscorrodebecauseweusetheminenvironmentswheretheyarechemicallyunstable.

mostmetals

arecommonly

intheformofvarious

chemicalcompounds(ores).Onlycopperandthepreciousmetals(gold,silver,platinum,etc.)arefoundinnatureintheirmetallicstate.smelting,refiningprocessescorrosionAllothermetalsareunstableandhaveatendencytoreverttotheirmorestablemineralforms.Somemetalsformprotectiveceramicfilms(passivefilms)ontheirsurfacesandtheseprevent,orslowdown,theircorrosionprocess.AnodizedtitaniumearringsThethicknessofthetitaniumoxideonthemetalsurfacerefractsthelightandcausestherainbowcolorsonherearrings.StainlesssteeleyeglassesThispassivefilmofonlyaboutadozenatomsthickcanbeprotective.1兵器：长期贮存，使用环境恶劣2交通运输：对铁轨、机车的腐蚀，对飞机零部件的腐蚀；（超高强度铝合金-应力腐蚀）船舶的海水腐蚀；3能源电力：火电有锅炉和管道的腐蚀，水电有水轮机组的腐蚀；核电站蒸汽发生器的腐蚀；（高镍合金-晶间腐蚀）煤矿安全；（井下湿度大、磨损腐蚀）石油，油气开采和运输造成设备和管道的腐蚀。4机械电子产品:机床、电器5化工设备：管道、锅炉、储存、阀门、冷凝；6建筑物:钢筋混凝土的盐害7民生：自来水管的锈蚀；8环境污染…UncontrolledcorrosionmayleadtodisastrousconsequencesLosscausedbycorrosion在化学工业、石油化工、造纸等工业中，金属腐蚀造成设备的跑、冒、滴、漏可造成大量有毒的物质泄漏，污染环境，危害人民的健康。因此，研究与解决材料的腐蚀问题，与防止环境污染、保护人民的健康息息相关.每年由于腐蚀可使大约10～20％的金属损失掉了。2003年世界的钢产量达到9.625亿吨，中国的钢产量高达2.2亿吨，美国的钢产量为0.914亿吨。按下限计算，世界每年腐蚀掉的钢大于美国的钢产量；中国一年就有2200万吨钢被腐蚀掉了，相当于腐蚀掉一个大型钢铁企业的年产量。腐蚀事故举例

1966年某天然气井的套管发生硫化物应力腐蚀开裂，造成井喷和特大爆炸，人员伤亡，日产百万立方米的高产气井报废。1971年某天然气管线发生腐蚀断裂，产生爆炸，直接经济损失达7000万元。1997年某化工厂年18个乙烯原料储罐由于硫化物腐储罐引起大火，停产半年，直接损失达2亿多元，，间接损失巨大。1985年日本的一架波音747客机，由于应力腐蚀断裂，死亡500余人。塔里木油田某井油管CO2腐蚀形貌图含硫输气管线沿着焊缝开裂失效按材料腐蚀形态均匀腐蚀不均匀腐蚀点蚀（孔蚀）缝隙腐蚀及丝状腐蚀电偶腐蚀（接触腐蚀）晶间腐蚀选择性腐蚀局部腐蚀全面腐蚀ClassificationofcorrosionCharacterofcorrosionbreakage:UniformCorrosion

(generalCorrosion)Thesurfaceeffectproducedbymostdirectchemicalattacks(e.g.,asbyanacid)isauniformetchingofthemetal.GalvanicCorrosion电偶腐蚀Galvaniccorrosionisanelectrochemicalactionoftwodissimilarmetalsinthepresenceofanelectrolyteandanelectronconductivepath.Itoccurswhendissimilarmetalsareincontact.Pittingcorrosion（点蚀）Pittingcorrosionislocalizedcorrosionthatoccursatmicroscopicdefectsonametalsurface.Thepitsareoftenfoundunderneathsurfacedepositscausedbycorrosionproductaccumulation.CreviceCorrosion缝隙腐蚀Creviceorcontactcorrosionisthecorrosionproducedattheregionofcontactofmetalswithmetalsormetalswithnonmetals.Itmayoccuratwashers,atsandgrains,underappliedprotectivefilms（薄膜）,andatpocketsformedbythreadedjoints.FiliformCorrosion丝状腐蚀Thistypeofcorrosionoccursonpaintedorplatedsurfaceswhenmoisturepermeatesthecoating.Longbranchingfilaments（细丝）ofcorrosionproductextendoutfromtheoriginalcorrosionpitandcausedegradationoftheprotectivecoating.IntergranularCorrosion

晶间腐蚀Intergranularcorrosionisanattackonor

adjacenttothegrainboundaries（晶界）

ofametaloralloy.StressCorrosionCracking

应力腐蚀断裂Stresscorrosioncracking(SCC)iscausedbythesimultaneouseffectsoftensilestress（拉应力）andaspecificcorrosiveenvironment.Stressesmaybeduetoappliedloads,residualstressesfromthemanufacturingprocess,oracombinationofboth.CorrosionFatigue

腐蚀疲劳Corrosionfatigueisaspecialcaseofstresscorrosioncausedbythecombinedeffectsofcyclicstress（循环应力）andcorrosion.Nometalisimmunefromsomereductionofitsresistancetocyclicstressingifthemetalisinacorrosiveenvironment.FrettingCorrosion

微动腐蚀Therapidcorrosionthatoccursattheinterfacebetweencontacting,highlyloadedmetalsurfaceswhensubjectedtoslightvibratorymotionsisknownasfrettingcorrosion.ErosionCorrosion磨损腐蚀Erosioncorrosionistheresultofacombinationofanaggressive（侵蚀性）chemicalenvironmentandhighfluidsurfacevelocities.Dealloying

脱合金成分腐蚀Dealloyingisarareformofcorrosionfoundincopperalloys,graycastiron,andsomeotheralloys.Dealloyingoccurswhenthealloylosestheactivecomponentofthemetalandretainsthemorecorrosionresistantcomponentinaporous“sponge”（海绵）onthemetalsurface.HydrogenDamage氢损伤Hydrogenembrittlementisaproblemwithhighstrengthsteels,titanium,andsomeothermetals.Controlisbyeliminatinghydrogenfromtheenvironmentorbytheuseofresistantalloys.MicrobialCorrosion微生物腐蚀Microbialcorrosion(alsocalledmicrobiologically-influencedcorrosionorMIC)iscorrosionthatiscausedbythepresenceandactivitiesofmicrobes（微生物）.Thiscorrosioncantakemanyformsandcanbecontrolledbybiocides（杀菌剂）orbyconventionalcorrosioncontrolmethods.ConcentrationCell

Corrosion浓差电池腐蚀Concentrationcellcorrosionoccurswhentwoormoreareasofametalsurfaceareincontactwithdifferentconcentrationsofthesamesolution.CorrosioninConcrete

混凝土腐蚀Concreteisawidely-usedstructuralmaterialthatisfrequentlyreinforcedwithcarbonsteelreinforcingrods（钢筋）,post-tensioningcableorprestressingwires.Thesteelisnecessarytomaintainthestrengthofthestructure,butitissubjecttocorrosion.ClassificationofcorrosionAccordingtocorrosionenvironments(腐蚀环境)Acorrosioninnatureenvironments(自然环境中的腐蚀)大气腐蚀、淡水和海水腐蚀、土壤腐蚀、细菌腐蚀Bcorrosioninindustrialenvironments(工业环境介质中的腐蚀)在酸性溶液中、碱性溶液中、盐类溶液、工业水、熔盐中的腐蚀。腐蚀分类Accordingtocorrosionmechanism(